On Apr 27, 2005, at 8:22 PM, Rob Studdert wrote:
I've set this procedure to a few people off list over the months and occasional
references to it seem to pop up on list. So I thought that after the recent
discussion I might as well post as it could be useful as a starting point for
others who haven't dabbled in RAW files.
I should mention too that since a lot of these adjustments are visual don't
expect to obtain optimum results if working on an uncalibrated system/monitor.
Rob's RAW procedure.
I have settled upon the following standard colour space, bit depth and size
(unless I've a very specific purpose): ProPhoto RGB, 16bits/Ch and 4096 by
2734, I have found these settings provide the optimal file for post processing,
editing and archiving. Though for most output purposes conversion back to 8
bits and sRGB or a printer specific colour space will be required before
sending files to the web or to print.
To make the adjustments tabled below "Advanced" mode needs to be selected at
the top of the Camera RAW control panel. I'll attempt to practically explain
the basic operation of each control panel tab:
"Adjust" Tab
Firstly I make any "White Balance" adjustments if required, I use the dropper
to set the white balance when I shoot a reference card and in some instances I
may tweak the "Temperature" manually to warm or cool an image.
Next I set the "Shadows", I may block up images shot in poor light or at high
ISO to get a more solid black but otherwise I just try to make the first data
on the histogram just touch the left edge of the histogram. Holding down the
"ALT" key whilst adjusting the slider will show precisely which areas of the
image will become blocked up.
Then "Exposure", if the image is under exposed I'll maximize the histogram so
that the data touches the right histogram edge. If the image has areas of
blocked up sky generally I'll leave the exposure but otherwise if the majority
of the data represents areas of specular reflections I might cut the data off,
just as I might purposefully block up an object shot on a white background.
Again holding down the "ALT" key whilst adjusting the slider will show
precisely which areas of the image will become blocked up.
Be careful when trying to reduce exposure significantly as this can lead to a
posterization effect in the highlight areas of the image.
The "Brightness" and "Contrast" controls don't change the black and white
points, they apply curves to the RAW data and are much more effective than
their implementations in post processing since the image is still in linear
gamma space before it's imported to the PS desk-top. Adjust for the required
visual effect.
"Saturation" adjustment is skipped for the moment.
"Lens" Tab
Set image magnification to 200% and move to a corner of the image that contains
sharp edge detail. I adjust the "Chromatic Aberration R/C" to provide the best
balance of edge CA reduction. Look at objects that are tangential to the
centre, not radial shifts or very high contrast edges (as H/C edges may also be
displaying sensor bloom). Holding down the "ALT" key whilst adjusting the
slider will highlight only the two colours being adjusted so it's easier to
determine the optimum setting.
Particularly prevalent CA may be further reduced by carefully trimming
"Chromatic Aberration B/Y" using the same procedure as above. Set image mag to
"fit in view" and trim the "Vignetting Amount" to offset any light drop-off
towards the image corners.
"Detail" Tab
Set image magnification to 100% and move to an area of the image that contains
sharp edge detail. Adjust the "Sharpness" for the best compromise between
enhancement of detail and lack of sharpening artifacts. Check across other
areas of the image to ensure that the sharpening setting doesn't cause
problems. I find that it's preferable to apply the minimum of sharpening at
this point, sharpening using PS tools will be more effective and bloom or noise
artifacts won't end up sharpened before they can be dealt with effectively.
Set image magnification to 200% and adjust "Color Noise Reduction" to just
eliminate colour noise in a darker area of the image. You will likely see a
slight reduction in saturation, this can be offset later by adjusting the
"Saturation" setting under the "Adjust" Tab. This option is useful to reduce
colour splotches in low light images and is difficult to replicate in post
processing.
Adjust "Luminance Smoothing" to just reduce surface noise, again be use none or
very little.
"Calibrate" Tab
Don't adjust anything here, the Pentax cameras seem quite well calibrated to
the PC CS RAW convertor.
Hit the OK button, you should then have an image in Photoshop that requires the
minimum of adjustment. Just to recap, remember that you need to convert the
profile to sRGB before saving for web but do it last after resizing and
sharpening etc. If the image is obviously noisy (IE high ISO shots in poor
light, or deep shaded areas) then sometimes it's best to not apply any
"Sharpeness" or "Luminance Smoothing" since third party NR plug-ins like Noise
Ninja or Neatimage may do a far better job of eliminating noise. However "Color
Noise Reduction" in the RAW convertor may still prove to be quite useful in
conjunction with these tools.
My PS CS RAW "Camera Default" has been pre-set to:
Shadows 3 Brightness 50 Contrast +25 Saturation +5 Sharpness 5 Luminance Smoothing 0 Color Noise 4
These starting points I've settled on because I tend to end up making fewer
adjustments if I use these factors as my starting points. However any
adjustments that are applied to any image are saved to a data base but they can
also be saved as a file in case you would like to keep the RAW file and
processing information together.
The convertor also allows the user to save only the lens parameters or any
other sub-set of variables using the "Save Settings Subset" dialogue. This
allows the same sub-set of parameters to be recalled and applied to any
subsequent image. For instance I have saved lens parameters for all my lenses
so that I can quickly apply the CA/vignett factors every time I use that
particular lens (f-stop and distance can change the CA though for several of my
more problematic lenses I have a few profiles saved).
Please let me know if you found this useful or if you have things to add or any
disputes over the content.
Cheers,
Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
